1. Field of the Invention
The present invention relates to a novel zoom lens and a novel imaging apparatus. In particular, the present invention relates to a zoom lens and an imaging apparatus equipped with the zoom lens. The zoom lens includes the function of correcting or reducing the blurring of a photographed image owing to camera shaking, or a camera shake correction/reduction function. The zoom lens is suitable for a photographing optical system of digital input-output equipment such as a digital still camera, a digital video camera and the like, and is compact, which achieves dimensions being thin in the depth direction of a camera.
2. Description of Related Art
In recent years, an imaging apparatus using a solid state imaging device, such as a digital still camera and the like, has been spreading. The imaging apparatus has been requested to have a higher image quality along with such wide spread of the digital still camera. In particular, for a digital still camera having a large number of pixels, for example, a photographing lens, especially a zoom lens adaptable to a solid state imaging device having a large number of pixels and has an excellent image forming performance has been sought. Moreover, the demands for miniaturization is also strong, and especially a zoom lens small-sized in the depth direction thereof is sought.
Moreover, the camera shake correction function preventing or reducing image blurring of a photographed image caused by camera shake at the time of photographing is also sought strongly.
For example, Japanese Patent Publication No. 3486532 proposes a zoom lens composed of a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive or negative refractive power, the zoom lens performing camera shake correction by moving the third lens group in a direction perpendicular to an optical axis.
Moreover, on the other hand, there has been proposed a zoom lens arranging a reflection member for bending the optical path in the first lens group to achieve the miniaturization in the depth direction, i.e. the shaping to be thin.
Accordingly, it is considerable to arrange the reflection member for bending the optical path in the first lens group and to shift an image by moving the whole or a part of the lens groups arranged on the image side of the first lens group in a direction perpendicular to the optical axis.
However, as described above, it is difficult to acquire a zoom lens having a sufficient optical performance only by simply combining the thin-shaped formation by the bending of the optical path in the reflection member and the image shifting method by lens shifting. In particular, aberration deterioration caused by decentrating of each composed lens group becomes large. That is, if it is tried to satisfy the image forming performance corresponding to a large number of pixels, assemblability with a high precision is required.